1. Field of the Invention
This invention relates to tube couplings and in Particular to tube couplings of the type described and illustrated in our U.K. Patent Nos. 1520742, 1573757 and 0255368.
2. Background Prior Art
U.K. Patent Publication No. 1,520,742 discloses a tube coupling comprising a body having a throughway open at one end to receive a tube, the throughway having a tapered cam surface extending towards said one end and a collet comprising an annular sleeve located in the open end of the throughway and having resilient arms projecting axially into the throughway. The resilient arms of the collet engage the tapered cam surface with movement of the collet outwardly of the throughway to grip and lock the tube in place. The tube is released from the collet by depressing the collet into the throughway.
U.K. Patent Publication No. 1,573,757 discloses a tube coupling of the form described and illustrated in U.K. Patent Specification No. 1,520,742 in which the resilient extending arms of the collet have outer faces shaped to which bear against the tapered cam surface adjacent the sleeve portion of the collet. The inner sides of the arms have inwardly facing projections spaced towards the free ends of the arms to produce positive engagement with the tube.
U.K. Patent Publication No. 2,132,296 discloses a tube coupling of the form described and illustrated in U.K. Patent Publication Nos. 1,520,742 and 1,573,757 in which the coupling body is provided with an end cover, having a base wall formed with an aperture through which a tube can extend into the coupling body and a peripheral wall to engage around the outer periphery of the coupling body. An attachment arrangement is provided between the peripheral wall of the end cover and coupling body which enables the cover to be removed when it is required to release the tube from the coupling body but which prevents the base wall of the cover being accidentally pressed into engagement with the projecting end of the collet from the coupling body which could inadvertantly release the tube from the coupling body.
European Patent Publication No. 0,255,368 discloses a tube coupling in which the end cover has manually operable members for engaging the projecting end of the collet to depress the collet into the throughway and thereby release the tube gripped in the coupling body.